docs: def clean(feed: "Feed") -> "Feed":
      """
      Apply
  
      #. :func:`drop_zombies`
      #. :func:`clean_ids`
      #. :func:`clean_times`
      #. :func:`clean_route_short_names`
  
      to the given "Feed" in that order.
      Return the resulting "Feed".
      """
      feed = feed.copy()
      ops = [
          "clean_ids",
          "clean_times",
          "clean_route_short_names",
          "drop_zombies",
      ]
      for op in ops:
          feed = globals()[op](feed)
  
      return feed